1. Field of the Invention
This invention relates to upright vacuum cleaners and, more specifically, to a nozzle lift mechanism for an upright vacuum cleaner which lifts a nozzle from a ground surface when a handle is pivoted to an upright position and which can be incrementally adjusted to position the nozzle at a preselected height from the ground surface during use.
2. Related Art
Vacuum cleaners come in many styles, including an upright type vacuum cleaner which comprise a foot and a pivotably-mounted elongated handle extending upwardly therefrom. The handle is generally grasped by the user to propel the foot over a surface to be cleaned. The foot is often provided with ground-engaging wheels to provide for easier movement over the surface to be cleaned. The foot typically includes an agitator brush rotatably mounted in a forward portion of the base. The agitator brush is typically mounted adjacent a suction inlet in the foot which receives any dirt and debris loosened by the action of the agitator brush. Suction is applied to the inlet and the dirt and debris are then collected in a bag for later disposal.
Vacuum cleaners are often used to clean both bare floors and carpets having varying thicknesses, pile, and shag characteristics. Thus, it is desirable to provide the vacuum cleaner with a height adjustment mechanism which positions the height of the suction inlet and agitator brush relative to the surface to be cleaned so as to dislodge the greatest amount of dirt and debris therefrom. Examples of prior art height adjustment mechanisms are disclosed in U.S. Pat. No. 4,467,495 (Fish et al.), U.S. Pat. No. 4,437,205 (Koland), U.S. Pat. No. 3,683,448 (Lagerstrom et al.), and U.S. Pat. No. 4,171,554 (Tschudy).
Further, it is also desirable to provide a vacuum cleaner with a nozzle lift mechanism which raises the suction inlet and agitator brush from the surface to be cleaned when the handle is pivoted to a non-use position, often generally vertical, to prevent damage to the surface when the agitator brush continues to rotate. Examples of prior art nozzle lift mechanisms are disclosed in U.S. Pat. No. 3,579,699 (Balzer), U.S. Pat. No. 4,782,552 (Bartlett et al.), U.S. Pat. No. 5,269,042 (Stephens et al.), U.S. Pat. No. 5,255,411 (Da Costa), U.S. Pat. No. 4,446,594 (Watanabe et al.) and U.S. Pat. No. 5,222,276 (Glenn III).
The height adjustment mechanism and nozzle lift mechanism must typically work in conjunction to prevent either mechanism from prohibiting the other from working properly. For example, the height adjustment mechanism must not lock the suction inlet and agitator brush at a particular height because the handle may be pivoted to the non-use position and actuate the nozzle lift mechanism to raise the suction inlet and agitator brush from the surface to be cleaned. If the height adjustment mechanism locks the suction inlet and agitator brush at a particular height, damage can occur to either or both of these mechanisms during use.
Prior art nozzle lift mechanisms and height adjustment mechanisms often require several parts and complicated assembly steps to install them in a base of a vacuum cleaner. A large number of parts and additional assembly steps can add to the manufacturing cost of a typical vacuum cleaner.
Other objects, features, and advantages of the invention will be apparent from the ensuing description in conjunction with the accompanying drawings.